skipping a line using amsthm package in a corollary

Question

  \documentclass[11pt, a4paper]{report}   
    \usepackage{bm}
    \usepackage{amsfonts, graphicx, verbatim, amsmath,amssymb, amsthm}
    \usepackage{color}
    \usepackage{array}
    \usepackage{setspace}% if you must (for double spacing thesis)
    \usepackage{fancyhdr}
    \usepackage{enumitem}
    \usepackage{tikz}
    \usepackage{parskip}

    \setlength{\textheight}{22cm}\setlength{\textwidth}{16cm}
    \setlength{\topmargin}{-1.25cm}
    \setlength{\oddsidemargin}{-0.5cm}\setlength{\evensidemargin}{-0.5cm}
    \setlength{\textheight}{24cm}\setlength{\textwidth}{16.5cm}
    \setlength{\topmargin}{-1.25cm}
    \setlength{\oddsidemargin}{0.5cm}\setlength{\evensidemargin}{0.5cm}
    \newtheorem{theorem}{Theorem}[section]
\newtheorem{acknowledgement}[theorem]{Acknowledgement}
\newtheorem{algorithm}[theorem]{Algorithm}
\newtheorem{axiom}[theorem]{Axiom}
\newtheorem{case}[theorem]{Case}
\newtheorem{claim}[theorem]{Claim}
\newtheorem{Theorem}[theorem]{Theorem}
\newtheorem{conclusion}[theorem]{Conclusion}
\newtheorem{condition}[theorem]{Condition}
\newtheorem{conjecture}[theorem]{Conjecture}
\newtheorem{Fact}[theorem]{Fact}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{criterion}[theorem]{Criterion}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{example}[theorem]{Example}
\newtheorem{exercise}[theorem]{Exercise}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{fact}[theorem]{Fact}
\newtheorem{lma}[theorem]{Lemma}
\newtheorem{notation}[theorem]{Notation}
\newtheorem{problem}[theorem]{Problem}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{Property}[theorem]{Property}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{Comment}[theorem]{Comment}
\newtheorem{solution}[theorem]{Solution}
\newtheorem{summary}[theorem]{Summary}
    \begin{document}
    \begin{corollary}

    \begin{enumerate}[label=(\roman*)]
    \item The degrees $n_i$ satisfy $\sum n_i^2 =g$
    \item If $s \in G$ is different from $1$, we have $\sum n_i \chi_i(s) =0$
    \end{enumerate}
    \end{corollary}
    \end{document}

I have the above MWE, I want to remove the "a" while keeping everything else the same.